In Windows XP, you can add a Local Area Connection network icon to your system tray so you can watch network activity. This icon consists of two small monitors, with the top one blinking when packets are received, the bottom when packets are sent, and both when traffic is going both ways, in and out of your computer's network card.
Well in Vista this icon is present by default in the system tray (in XP you had to enable it on the properties sheet for your connection) but it doesn't blink or do anything. Maybe that's because some users find it annoying to see blinking lights out of the corner of their eye when they're working on their computer.
But you can enable this indicator of network activity in Vista, simply right-click on the icon and select Turn On Activity Animation, and now you have an indicator you can watch to help you diagnose problems when network connectivity seems to be down.
Cheers, Mitch Tulloch, MVP
Note: This tip is based on a pre-release version of Windows Vista and may not reflect functionality in the final product.